Catalytic hydroprocessing is commonly used to form lubricant base oils from suitable feeds. The hydroprocessing can typically include one or more of hydrotreatment for removal of heteroatoms, hydrocracking for improvement of viscosity index, catalytic dewaxing for improvement of cold flow properties, and hydrofinishing to reduce or minimize the amount of aromatics. While a broad range of processing conditions can potentially be used for each type of hydroprocessing, in practice the conditions between hydroprocessing steps used on a single feed can typically be related in order to allow for efficient use of refinery resources.
U.S. Patent Application Publication 2012/0261307 describes an integrated process for, hydrotreating, hydrocracking and dewaxing of a feed to form fuels and lubricant products. The integrated process includes use of three hydroprocessing stages, with a high pressure stripping/separating zone between the first and second stage. The high pressure and temperature stripping/separating zone operates with no disengagement between or following the hydroprocessing zones. This can allow the process pressure to be greatest at the entrance to the first hydroprocessing zone.
U.S. Patent Application Publication 2013/0341243 describes a hydrocracking process selective for improved distillate and improved lube yield and properties. A two-stage hydrocracking catalyst can be used for hydrocracking of a feed to form a converted portion suitable for diesel fuel production and an unconverted portion suitable for production of lubricant base oils. The two-stage hydrocracking catalyst can correspond to a first stage catalyst including Pd and/or Pt supported on USY and a second stage catalyst including Pd and/or Pt supported on ZSM-48.
U.S. Patent Application Publication 2013/0158314 describes a multi-stage aromatic saturation process. Although higher pressures are described for hydrotreatment and hydrocracking of a feedstock, the highest hydrogen partial pressure described for an aromatic saturation process is 1000 psia (6.9 MPa) or less.